The easy answer and one that you probably didn't want to hear, the universe is infinite in size. Whilst the Earth is a finite size, we know it is 3,959 miles according Bing. The same can't be said for the Universe, we don't know how big it is. The simple truth is we don't know.
The farthest object so far discovered is a galaxy known as EGS8p7 (EGSY-2008532660) which is located in the constellation of Ursa Major in the northern hemisphere. If you search the internet for farthest galaxy discovered, you may get a different answer. I base the statement on the most recent article that I could find on the subject which in this case is the article from Nature World which was written in October 2015. Scientists might find a further galaxy and in which case this article will be out of date.
The galaxy is 13.2 Billion years old and the light has been travelling at light speed since that time. It was born about 500-600 million years after the big bang occurred, galaxies didn't just pop into existence, they evolved. However as the universe is expanding, the galaxy will have moved away further from us since then and therefore will be further away than 13.2 billion light years. There's most likely a galaxy that is even further away from us than that but its light has not reached us and will not see in our life times. If that's the case, a galaxy farther away then the Big Bang happened a lot earlier than we thought. EGS8p7 galaxy is not visible with the naked eye so you won't be able to see when you look up in the sky.
According to Universe Today, the observable universe has a diameter of 92 billion light years across. The reasoning for this is the cosmic background radiation which is the left overs of the big bang. When you turn on an untuned television, you see static, that is radiation from the beginning of time.
The universe is expanding at the speed of light ref:Cornell University and light from EGS8p7 will one day disappear from our skies. The galaxy will still exist but any evidence to indicate its existence will have disappeared. There is a theory that if all the light from every galaxy, both local and distant was visible, space would be white not black.
Our universe may well be just one of many universes in a Multiverse, one universe in side a bubble with another bubble nearby, relatively speaking. If there is a bubble multiverse then may space is bigger than we could ever imagine. There are different types of possible multiverses and the bubble is just one.
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